Activated base metal catalysts

ABSTRACT

Nitro-compounds are hydrogenated with an activated Ni catalyst that is doped during and/or after activation with one or more elements from the list of Mg, Ca, Ba, Ti, Zr, Ce, Nb, Cr, Mo, W, Mn, Re, Fe, Co, Ir, Ni, Cu, Ag, Au, Rh, Ru and Bi whereas the Ni/Al alloy may not, but preferentially can contain prior to activation one or more doping elements from the list of Ti, Ce, V, Cr, Mo, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt and Bi. If the Ni/Al alloy contained one or more of the above mentioned suitable alloy doping elements prior to activation, the resulting catalyst can then be doped with one or more of the elements from the list of Mg, Ca, Ba, Ti, Zr, Ce, V, Nb, Cr, Mo, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au and Bi by their adsorption onto the surface of the catalyst.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is US national stage of internationalapplication PCT/EP2007/055186, which had an international filing date ofMay 29, 2007, and which was published in English under PCT Article 21(2)on Dec. 4, 2008.

The invention concerns an activated base metal catalyst, and its use forthe hydrogenation of nitro-compounds.

Activated metal catalysts are also known in the fields of chemistry andchemical engineering as Raney-type, sponge and/or skeletal catalysts.They are used, largely in powder form, for a large number ofhydrogenation, dehydrogenation, isomerization, reductive amination,reductive alkylation and hydration reactions of organic compounds. Thesepowdered catalysts are prepared from an alloy of one or morecatalytically-active metals, also referred to herein as the catalystmetals, with a further alloying component which is soluble in alkalis.Mainly nickel, cobalt, copper, iron or combinations thereof are used ascatalyst metals. Aluminum is generally used as the alloying componentwhich is soluble in alkalis, but other components may also be used, inparticular zinc and silicon or mixtures of these either with or withoutaluminum.

These so-called Raney alloys are generally prepared by the ingot castingprocess. In that process a mixture of the catalyst metal and, forexample, aluminum is first melted and casted into ingots.

Typical alloy batches on a production scale amount to about ten to acouple hundred kg per ingot. According to DE 21 59 736 cooling times ofup to two hours were obtained for this method. This corresponds to anaverage rate of cooling of about 0.2 K/s. In contrast to this, rates of10² to 10⁶ K/s and higher are achieved in processes where rapid coolingis applied (for example an atomizing process). The rate of cooling isaffected in particular by the particle size and the cooling medium (seeMaterials Science and Technology edited by R. W. Chan, P. Haasen, E. J.Kramer, Vol. 15, Processing of Metals and Alloys, 1991, VCH-VerlagWeinheim, pages 57 to 110). A process of this type is used in EP 0 437788 B 1 in order to prepare a Raney alloy powder. In that process themolten alloy at a temperature of 5 to 500° C. above its melting point isatomized and cooled using water and/or a gas.

To prepare a powder catalyst, the Raney alloy which can be made by aknown process (i.e. according to EP 0 437 788 B1) is first finelymilled, if it has not been produced in the desired powder form duringpreparation. Then the aluminum is partly (and if need be, totally)removed by extraction with alkalis such as, for example, caustic sodasolution (other bases such as KOH are also suitable) to activate thealloy powder. These types of catalysts can be activated with most basesand acids to give varying results. Following extraction of the aluminum,the remaining catalytic power has a high specific surface area (BET),between 5 and 150 m²/g, and is rich in active hydrogen. The activatedcatalyst powder is pyrophoric and stored under water or organic solventsor is embedded in organic compounds (e.g., distearylamine) which aresolid at room temperature.

U.S. Pat. No. 6,423,872 describes the use of Ni catalysts that containless than 5.5 wt % Al for the hydrogenation of nitrated aromatics. Itdescribes the use of both commercially available standard activated Nicatalysts and supported Ni catalysts for the hydrogenation of nitratedaromatics, where problematic nickel aluminates are formed during thishydrogenation if their Al content is 5.5 wt % Al or higher.

These nickel aluminates can be in the form of takovite and/ortakovite-like compounds and all of these nickel aluminates need to beremoved from the desired amine before it is processed further. Thesenickel aluminates tend to form solids in the reactor and in theperipheral equipment (e.g., piping, settling tanks, filtrationequipment, pumps and other equipment used in this process) that candeposit on their walls to decrease their heat transfer efficiency and tocreate blockages in the system.

Hence the formation of these nickel aluminates creates both safetyhazards and a drop in productivity. The buildup of these nickelaluminates make it difficult to continue with the reaction and in suchcases, one needs to shutdown the plant and clean out these deposits fromthe reactor and the peripheral equipment.

U.S. Pat. No. 6,423,872 also mentions the use of very specific alloydopants limited to a definite list of elements that remain in theactivated Ni catalyst after activation with caustic and the use of theseresulting catalysts for the continuous hydrogenation of nitratedaromatics.

The conventional alloy doping elements from the groups IVA, VA, VIA andVIII of the periodic table of elements were specifically claimed in thispatent. Additional Alloy doping elements such as titanium iron andchromium were also claimed.

U.S. Pat. No. 6,423,872 describes the use of a Ni catalyst having lessthan 5.5 wt % Al for the continuous hydrogenation of nitrated aromaticsdue to its lower formation of undesirable nickel aluminates during thishydrogenation. In principle, the less Al you have in the catalyst, thelower the amount of the nickel aluminates you will form. However thesecatalysts still form nickel aluminates and this technology does have itslimits since the Al that is present in them is still considerablyleachable under the conditions used for the hydrogenation ofnitro-compounds such as nitrated aromatics.

U.S. Pat. No. 6,423,872 keeps the Al level lower than 5.5 wt % bychanging the Al content of the alloy and/or increasing the intensity ofthe activation process. Increasing the Al content in the alloy willincrease the amounts of Al-rich and more readily leachable phases suchas NiAl₃ and the Al-eutectic phases. Another way to increase the amountsof these phases would be to perform the appropriate heat treatment tothe alloy either after or during its production. Increasing the amountsof these readily leachable phases can also decrease the mechanicalstability of these catalysts, thereby leading to a lower lifetime forthe catalysts.

Hence lowering the Al content of the catalyst simply by increasing theamount of leachable phases in the precursor alloy does have itslimitations.

Another method that U.S. Pat. No. 6,423,872 describes to decrease the Alcontent in the catalyst was to increase the intensity of the activationprocess by increasing the leaching temperature, pressure and otherparameters that accelerate this process. However, not only does thisincrease the cost of the catalyst, but it also produces a sodiumaluminate side product that is not salable and would need to be disposedof. Moreover if one is not careful during leaching, the newly formedsodium aluminate under these harsher conditions may deposit back on tothe catalyst and block its catalytically active surface leading to loweractivity and shorter catalyst life.

While the methods of U.S. Pat. No. 6,423,872 do decrease the level ofleachable Al to some degree, they do not entirely solve the problemsinvolved with the hydrogen of nitro-compounds, since most alloyactivations used in catalyst production occur under different conditionsthan those of the continuous hydrogenation of nitro-compounds such asnitrated aromatic compounds. Thus the commercially applicable methods ofU.S. Pat. No. 6,423,872 produce a catalyst that still has a considerableamount of Al in the catalyst that can be leached out during thehydrogenation of nitrated aromatic compounds.

Hence it is a goal of the present invention to produce a catalyst thatgenerates lower levels of nickel aluminates buy minimizing theleachability of the remaining Al in the catalyst, regardless of thelevel of Al.

Surprisingly this problem is solved with activated Ni catalystsaccording to the invention.

The formation of takovite during the hydrogenation of nitro-compoundswith an activated base metal catalyst can be greatly reduced, or eveneliminated, by doping the catalyst with one or more elements from thelist of Mg, Ca, Ba, Ti, Zr, Ce, Nb, Cr, Mo, W, Mn, Re, Fe, Co, Ir, Ni,Cu, Ag, Au, Bi, Rh and Ru by adsorption onto the surface of the catalystduring and/or after activation of the precursor alloy. The adsorption ofone or more of the above mentioned elements after activation includesbefore, during and/or after washing the catalyst subsequent toactivation. The adsorption of the doping element(s) can take place withexisting compounds of the doping element(s) and/or with compounds of thedoping element(s) that are formed in-situ during the doping process. Theadsorption of the doping element(s) normally takes place in a liquidphase and the compounds of the doping elements can be soluble in theliquid medium or only slightly soluble in the liquid phase so that therate of doping can be controlled by the solubility determinedconcentration of the doping element(s) in the slurry phase. One couldalso add inhibitors (e.g., chelating agents), accelerators (e.g.,precipitating agents) and combinations thereof that control the rate ofadsorption of the doping element(s) on to the catalytic surface. Onecould also use the gas phase to adsorb doping elements provided thatcare is taken to prevent the excessive oxidation and deactivation of thecatalyst. In such cases, it could actually be possible to adsorb thepromoting element(s) via techniques such as evaporation, sublimation andsputtering onto the catalytic surface. This use of adsorption methodsfor the doping of the catalyst is clearly different than the addition ofthe doping element(s) to the alloy prior to activation in that theadsorption method concentrates the doping element(s) onto the surface ofthe catalyst with very little, if any at all, of the doping element(s)being in the bulk of the catalyst particle. This surprisingly helps ininhibiting the formation of takovite. The preferred doping elements ofthe above mentioned list to be adsorbed onto the catalyst are Cr, Mo,Fe, Co, Ni, Cu, Ag and Au.

A further preferred embodiment of this invention is the addition of oneor more of the doping elements from the list of Ti, Ce, V, Cr, Mo, W,Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt and Bi to the precursor alloy beforeactivation followed by the adsorption of one or more doping elementsfrom the list of Mg, Ca, Ba, Ti, Zr, Ce, V, Nb, Cr, Mo, W, Mn, Re, Fe,Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au and Bi during and/or after theactivation of the alloy. In this preferred embodiment, the adsorbeddoping element(s) may be added before, during and/or after washing thecatalyst subsequent to its activation. The preferred elements for thedoping in the alloy are one of more from the list of Ti, Ce, Cr, V, Mo,Fe, Ru, Pd, Pt and Co and the preferred elements for the subsequentdoping via adsorption are Mg, Cr, V, Mo, Fe, Co, Ni, Cu, Ru, Pd, Pt, Agand Au. The catalyst produced by introducing one or more of the abovementioned doping elements into the alloy followed by the adsorption ofone or more of different and/or the same doping elements from the listmentioned above was found to be advantageous for the hydrogenation ofnitro-compounds while greatly reducing, and in some cases eliminating,the formation of takovite.

The doping level of the preferred catalysts can range from 0.01 wt % to10 wt % for each doping element and the Al content ranges from 0.05 wt %to 10 wt %.

Optimally the catalysts can contain between 0.01 and 1.9 wt.-% Fe.

Optimally the catalysts can contain between 0.01 and 2.4 wt.-% Cr.

Optimally the catalysts can contain between 0.01 and 1.9 wt.-% Fe andcontain between 0.01 and 2.4 wt.-% Cr.

An especially useful catalyst for the hydrogenation of nitro-compoundswithout the formation of takovite was found to be a Ni/Al catalyst thatwas doped with Cu in combination with one or more elements from the listof Mg, Ti, Ce, V, Cr, Mo, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt and Bivia their adsorption during and/or after the activation of the alloy.The preferred catalysts from this part of the present invention includethe doping of the catalyst via adsorption with Cu together with one ormore elements from the list of Mg, V, Cr, Mo, Fe, Ru, Co, Pd, Pt, Ag andAu. Another catalyst of this invention also includes doping the Ni/Alalloy with one or more elements from the list of Ti, Ce, V, Cr, Mo, W,Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt and Bi before activation followed bythe adsorption of Cu onto the catalyst during and/or after theactivation process. The catalyst of this invention can also be made bydoping the Ni/Al alloy with one or more elements from the list of Ti,Ce, V, Cr, Mo, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt and Bi beforeactivation followed by the adsorption of Cu together with one or moredoping from the list of Mg, Ti, Ce, V, Cr, Mo, W, Mn, Re, Fe, Ru, Co,Rh, Ir, Pd, Pt and Bi onto the catalyst during and/or after theactivation process.

An especially useful catalyst for the hydrogenation of nitro-compoundswithout the formation of takovite was found to be a Ni/Al catalyst thatwas doped with Mo in combination with one or more elements from the listof Mg, Ti, Ce, V, Cr, Cu, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt and Bivia their adsorption during and/or after the activation of the alloy.The preferred catalysts from this part of the present invention includethe doping of the catalyst via adsorption with Mo together with one ormore elements from the list of Mg, V, Cr, Cu, Fe, Ru, Co, Pd, Pt, Ag andAu. Another catalyst of this invention also includes doping the Ni/Alalloy with one or more elements from the list of Ti, Ce, V, Cr, Mo, W,Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt and Bi before activation followed bythe adsorption of Mo onto the catalyst during and/or after theactivation process. The catalyst of this invention can also be made bydoping the Ni/Al alloy with one or more elements from the list of Ti,Ce, V, Cr, Mo, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt and Bi beforeactivation followed by the adsorption of Mo together with one or moredoping from the list of Mg, Ti, Ce, V, Cr, Cu, W, Mn, Re, Fe, Ru, Co,Rh, Ir, Pd, Pt and Bi onto the catalyst during and/or after theactivation process.

An especially useful catalyst for the hydrogenation of nitro-compoundswithout the formation of takovite was found to be a Ni/Al catalyst thatwas doped with Cr in combination with one or more elements from the listof Mg, Ti, Ce, V, Cr, Mo, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt and Bivia their adsorption during and/or after the activation of the alloy.The preferred catalysts from this part of the present invention includethe doping of the catalyst via adsorption with Cr together with one ormore elements from the list of Mg, V, Cu, Mo, Fe, Ru, Co, Pd, Pt, Ag andAu. Another catalyst of this invention also includes doping the Ni/Alalloy with one or more elements from the list of Ti, Ce, V, Cr, Mo, W,Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt and Bi before activation followed bythe adsorption of Cr onto the catalyst during and/or after theactivation process. The catalyst of this invention can also be made bydoping the Ni/Al alloy with one or more elements from the list of Ti,Ce, V, Cr, Mo, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt and Bi beforeactivation followed by the adsorption of Cr together with one or moredoping from the list of Mg, Ti, Ce, V, Cu, Mo, W, Mn, Re, Fe, Ru, Co,Rh, Ir, Pd, Pt and Bi onto the catalyst during and/or after theactivation process.

The powdered activated base metal catalysts (Raney-type catalysts) aretypically used in either batch or continuous processes with stirred tankreactors. Batch processes are very flexible and under the rightconditions, they are very economical for the hydrogenation ofnitro-compounds to amines.

Another method involves the use of these powder catalysts in loopreactors where the reaction could occur in the vapor, trickle, aerosolor liquid phase. Loop, tube and stirred tank reactors can be usedcontinuously for this process, where the nitro-compound is fed into thereactor at a rate in which it is immediately hydrogenated to completionor in some cases almost to completion when a second hydrogenationreactor (or even more) is used to hydrogenate the remaining amounts ofthe nitro-compound and its possible intermediates. During the continuoushydrogenation process, the same amount of the desired amine is removedfrom of the reaction system at the same rate as the nitro-compound isadded to maintain the overall volume of the reaction medium in thereactor. In the case of loop and tube reactors, this reaction may bedone in a circulation mode where the nitro-compound is introduced in onepart of the circulating reaction stream and the finished product mixtureis taken out of another part.

This reaction can take place in the presence of one or more solvents(for example but not limited to alcohols such as methanol and ethanol)or it can take place in the product mixture of the resulting amine andwater. The advantages of using the product mixture for the reactionmedium is that one does not need to buy the solvent and it does not needto be removed from the reaction mixture or possibly purified beforebeing used again. Another option would be to perform the reaction inonly the desired amine and to use a high enough reaction temperature sothat the water is immediately distilled away from the reaction slurryand so that the desired amine remains in a liquid form. This isespecially important for amines such as toluenediamine, where it needsto be kept in the molten state if it is to be used as the reactionmedium without the assistance of solvents that maintain the liquidproperties of the reaction slurry.

In general, the powder catalysts of this invention can be used in anyreaction system and in any reaction process that is suitable for thehydrogenation of nitro-compounds to amines that utilize powdercatalysts.

This invention includes the process for the hydrogenation ofnitro-compounds with an activated Ni catalyst which is characterized inthat is doped with one or more elements from the list of Mg, Ca, Ba, Ti,Zr, Ce, Nb, Cr, Mo, W, Mn, Re, Fe, Co, Ir, Ni, Cu, Ag, Au, Bi, Rh and Ruby adsorption onto the surface of the catalyst during and/or afteractivation of the precursor alloy as described previously. The preferreddoping elements of the above mentioned list to be adsorbed onto thecatalyst are Cr, Mo, Fe, Co, Ni, Cu, Ag and Au. The doping level of thepreferred catalyst can range from 0.01 wt % to 10 wt % for each dopingelement and the Al content ranges from 0.05 wt % to 10 wt %.

A further embodiment of this invention is the process for thehydrogenation of nitro-compounds with an activated Ni catalyst which isdoped with one or more elements from the list of Ti, Ce, V, Cr, Mo, W,Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt and Bi to the precursor alloy beforeactivation followed by the adsorption of one or more doping elementsfrom the list of Mg, Ca, Ba, Ti, Zr, Ce, V, Nb, Cr, Mo, W, Mn, Re, Fe,Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au and Bi during and/or after theactivation of the alloy. In this preferred embodiment, the adsorbeddoping element(s) may be added before, during and/or after washing thecatalyst subsequent to its activation. The preferred elements for thedoping in the alloy are one of more from the list of Ti, Ce, Cr, V, Mo,Fe, Ru, Pd, Pt and Co and the preferred elements for the subsequentdoping via adsorption are Mg, Cr, V, Mo, Fe, Co, Ni, Cu, Ru, Pd, Pt, Agand Au. The doping level of the preferred catalyst can range from 0.01wt % to 10 wt % for each doping element and the Al content ranges from0.05 wt % to 10 wt %.

This invention includes the process for the hydrogenation of nitratedaromatics with an activated Ni catalyst which is characterized in thatis doped with one or more elements from the list of Mg, Ca, Ba, Ti, Zr,Ce, Nb, Cr, Mo, W, Mn, Re, Fe, Co, Ir, Ni, Cu, Ag, Au, Bi, Rh and Ru byadsorption onto the surface of the catalyst during and/or afteractivation of the precursor alloy as described previously. The preferreddoping elements of the above mentioned list to be adsorbed onto thecatalyst are Cr, Mo, Fe, Co, Ni, Cu, Ag and Au. The doping level of thepreferred catalyst can range from 0.01 wt % to 10 wt % for each dopingelement and the Al content ranges from 0.05 wt % to 10 wt %.

A further embodiment of this invention is the process for thehydrogenation of nitrated aromatics with an activated Ni catalyst whichis doped with one or more elements from the list of Ti, Ce, V, Cr, Mo,W, Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt and Bi to the precursor alloybefore activation followed by the adsorption of one or more dopingelements from the list of Mg, Ca, Ba, Ti, Zr, Ce, V, Nb, Cr, Mo, W, Mn,Re, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au and Bi during and/orafter the activation of the alloy. In this preferred embodiment, theadsorbed doping element(s) may be added before, during and/or afterwashing the catalyst subsequent to its activation. The preferredelements for the doping in the alloy are one of more from the list ofTi, Ce, Cr, V, Mo, Fe, Ru, Pd, Pt and Co and the preferred elements forthe subsequent doping via adsorption are Mg, Cr, V, Mo, Fe, Co, Ni, Cu,Ru, Pd, Pt, Ag and Au. The doping level of the preferred catalyst canrange from 0.01 wt % to 10 wt % for each doping element and the Alcontent ranges from 0.05 wt % to 10 wt %.

This invention includes the process for the continuous hydrogenation ofnitrated aromatics with an activated Ni catalyst which is characterizedin that is doped with one or more elements from the list of Mg, Ca, Ba,Ti, Zr, Ce, Nb, Cr, Mo, W, Mn, Re, Fe, Co, Ir, Ni, Cu, Ag, Au, Bi, Rhand Ru by adsorption onto the surface of the catalyst during and/orafter activation of the precursor alloy as described previously. Thepreferred doping elements of the above mentioned list to be adsorbedonto the catalyst are Cr, Mo, Fe, Co, Ni, Cu, Ag and Au. The dopinglevel of the preferred catalyst can range from 0.01 wt % to 10 wt % foreach doping element and the Al content ranges from 0.05 wt % to 10 wt %.

A further embodiment of this invention is the continuous process for thehydrogenation of nitrated aromatics with an activated Ni catalyst whichis doped with one or more elements from the list of Ti, Ce, V, Cr, Mo,W, Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt and Bi to the precursor alloybefore activation followed by the adsorption of one or more dopingelements from the list of Mg, Ca, Ba, Ti, Zr, Ce, V, Nb, Cr, Mo, W, Mn,Re, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au and Bi during and/orafter the activation of the alloy. In this preferred embodiment, theadsorbed doping element(s) may be added before, during and/or afterwashing the catalyst subsequent to its activation. The preferredelements for the doping in the alloy are one of more from the list ofTi, Ce, Cr, V, Mo, Fe, Ru, Pd, Pt and Co and the preferred elements forthe subsequent doping via adsorption are Mg, Cr, V, Mo, Fe, Co, Ni, Cu,Ru, Pd, Pt, Ag and Au. The doping level of the preferred catalyst canrange from 0.01 wt % to 10 wt % for each doping element and the Alcontent ranges from 0.05 wt % to 10 wt %.

There are many types of nitro-compound hydrogenations performed inindustry. One of the more commercially interesting and technicallychallenging is the hydrogenation of dinitrotoluene (DNT) totoluenediamine (TDA). This hydrogenation is performed with activated Nicatalysts at temperatures ranging from room temperature to 210° C. andpressures ranging from atmospheric pressure to 200 bar. The preferredreaction conditions are within the ranges of 50° to 180° C. and 3 to 80bar. This reaction can be performed in an excess of hydrogen or under astoichiometric amount of hydrogen.

In U.S. Pat. No. 6,423,872, the reaction conditions for the continuoushydrogenation of DNT were 20 bar hydrogen at 150° C. with 0.7 grams ofactivated Ni catalyst and a DNT feed that kept the level of DNT below1000 ppm during this hydrogenation. In U.S. Pat. No. 3,935,264, thehydrogenation of DNT was performed with methanol as a solvent under thepressure of 28.5 bar hydrogen and 120° C. over the activated Nicatalyst.

Recently in U.S. Pat. No. 6,005,143, it was found that one could achievesatisfactory results for the hydrogenation of DNT to TDA over a Ni/Pdcatalyst supported on a monolith in the presence of methanol with 16 barhydrogen and temperatures ranging from 135 to 155° C.

Typically fixed bed hydrogenation processes require higher hydrogenpressures than their slurry phase counterparts, indicating thatpressures of ˜16 Bar should also be suitable for the reactions performedhere. U.S. Pat. No. 4,224,249 also showed this to be true as aRaney-type Ni catalyst was successfully used at 130° C. and 160 psig (12bar) for the hydrogenation of dinitrotoluene (DNT) in both the batch andthe incremental feed modes of operation. The incremental feed mode ofoperation was used to simulate the conditions in which DNT iscontinuously hydrogenated on a industrial scale.

The hydrogenation of nitro-compounds can take place in the vapor,slurry, trickle, aerosol and/or liquid phase. The reaction could beperformed as a batch process or it could be performed as a continuousprocess. The continuous processes may involve, but they are not limitedto, a type of circulation process. This invention also includes acontinuous process where the nitro-compound is added at a rate that isthe same or slower than the rate of hydrogenation, so that theconcentration of the nitro-compound is kept to a very low level. Thefeeding rate of the nitro-compound may be so low that the level of thenitro-compound is 1000 ppm or lower. This invention also includes theuse of the previously mentioned catalyst of this invention in acontinuous process that utilizes a second hydrogenation reactor (ormore) to hydrogenate any nitro-compounds and/or intermediates that areremaining from the hydrogenation in the first hydrogenation reactor.

The nitro-compound hydrogenation of this invention may take place in thepresence of the neat nitro-compound, at high concentrations of thereactant, at very low concentrations of the reactant and/or in thepresence of the product mixture that would be acting like a solvent.This hydrogenation may also take place in the presence of practicallyonly the desired amine if the water is removed in a satisfactory method(e.g., distillation) during the reaction. The nitro-compoundhydrogenation of this invention may take place in the presence of asolvent. The reactor type could be, but is not limited to, a stirredtank reactor, a continuous stirred tank reactor, a loop reactor or atube reactor. This nitro-compound hydrogenation may occur betweenatmospheric pressure and 200 bars of hydrogen and the temperature canrange from ˜10° C. to 210° C.

This invention encompasses the hydrogenation of nitrated aromatics andthis may occur either as a batch or a continuous process over the abovementioned catalysts. This invention also includes the hydrogenation ofDNT to TDA as either a batch process or a continuous process with theabove described catalysts.

This invention also includes the catalysts having the followingproperties:

An activated Ni/Al catalyst that was doped with Cu via adsorption ontothe surface of the catalyst during and/or after activation incombination with one or more elements from the list of Mg, Ti, Ce, V,Cr, Mo, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt, Bi, Ag and Au via theiradsorption during and/or after the activation of the alloy. Thepreferred catalysts from this part of the present invention include thedoping of the catalyst via adsorption with Cu together with one or moreelements from the list of Mg, V, Cr, Mo, Fe, Co, Pd, Pt and Au. Anothercatalyst of this invention also includes doping the Ni/Al alloy with oneor more elements from the list of Mg, Ti, Ce, V, Cr, Mo, W, Mn, Re, Fe,Ru, Co, Rh, Ir, Pd, Pt and Bi before activation followed by theadsorption of Cu onto the catalyst during and/or after the activationprocess. The catalyst of this invention can also be made by doping theNi/Al alloy with one or more elements from the list of Mg, Ti, Ce, V,Cr, Mo, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt and Bi before activationfollowed by the adsorption of Cu together with one or more doping fromthe list of Mg, Ti, Ce, V, Cr, Mo, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Pd,Pt, Bi, Ag and Au onto the catalyst during and/or after the activationprocess.

An activated Ni/Al catalyst that was doped with Mo in combination withone or more elements from the list of Mg, Ti, Ce, V, Cr, Cu, W, Mn, Re,Fe, Ru, Co, Rh, Ir, Pd, Pt, Bi, Ag and Au via their adsorption duringand/or after the activation of the alloy. The preferred catalysts fromthis part of the present invention include the doping of the catalystvia adsorption with Mo together with one or more elements from the listof Mg, V, Cr, Cu, Fe, Pd, Pt and Au. Another catalyst of this inventionalso includes doping the Ni/Al alloy with one or more elements from thelist of Mg, Ti, Ce, V, Cr, Mo, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt andBi before activation followed by the adsorption of Mo onto the catalystduring and/or after the activation process. The catalyst of thisinvention can also be made by doping the Ni/Al alloy with one or moreelements from the list of Mg, Ti, Ce, V, Cr, Mo, W, Mn, Re, Fe, Ru, Co,Rh, Ir, Pd, Pt and Bi before activation followed by the adsorption of Motogether with one or more doping from the list of Mg, Ti, Ce, V, Cr, Cu,W, Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt, Bi, Ag and Au onto the catalystduring and/or after the activation process.

An activated Ni/Al catalyst that was doped with Cr in combination withone or more elements from the list of Mg, Ti, Ce, V, Cu, Mo, W, Mn, Re,Fe, Ru, Co, Rh, Ir, Pd, Pt, Bi, Ag and Au via their adsorption duringand/or after the activation of the alloy. The preferred catalysts fromthis part of the present invention include the doping of the catalystvia adsorption with Cr together with one or more elements from the listof Mg, V, Cu, Mo, Fe, Co, Pd, Pt and Au. Another catalyst of thisinvention also includes doping the Ni/Al alloy with one or more elementsfrom the list of Mg, Ti, Ce, V, Cr, Mo, W, Mn, Re, Fe, Ru, Co, Rh, Ir,Pd, Pt and Bi before activation followed by the adsorption of Cr ontothe catalyst during and/or after the activation process. The catalyst ofthis invention can also be made by doping the Ni/Al alloy with one ormore elements from the list of Mg, Ti, Ce, V, Cr, Mo, W, Mn, Re, Fe, Ru,Co, Rh, Ir, Pd, Pt and Bi before activation followed by the adsorptionof Cr together with one or more doping from the list of Mg, Ti, Ce, V,Cu, Mo, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Pd, Pt, Bi, Ag and Au onto thecatalyst during and/or after the activation process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing DNT pulse hyd genation data for CE1, CE2, CE3,E1 and E2.

FIG. 2 is a graph showing DNT pulse hydrogenation data for CE1, CE2,CE3, E3, E4, E5, E6 and E7.

APPLICATION EXAMPLE 1

The pulse hydrogenation of dinitrotoluene (DNT) to toluenediamine (TDA).

DNT is typically hydrogenated in an industrial setting via a continuousmode, where the DNT feed rate is slow enough to keep its concentrationlow enough so that it doesn't poison the catalyst or become a safetyhazard. This means that the hydrogenation rate will be dependent of theDNT feed rate. The goal of our pulse hydrogenation method was to keepthe DNT concentration low enough so that it would be comparable to theindustrial setting while measuring the activity of the catalyst. We wereable to do so by pulsing in the DNT feed at a rate that was slightlyfaster than the rate of hydrogenation so that we could measure catalystactivity while keeping the time of the slight excess of DNT to aminimum. It was also decided to use the reaction pressure andtemperature conditions similar to those described in U.S. Pat. No.4,224,249, U.S. Pat. No. 6,423,872 and U.S. Pat. No. 6,005,143.

The pulse hydrogenation method was started by placing 150 or 300milligrams of catalyst, 101 grams of TDA and 59 grams of water (thereaction's stoichiometric TDA-to-water ratio) into a 500 ml autoclave.The autoclave was then closed, purged with nitrogen 3 times, purged withhydrogen 3 times and heated to the reaction temperature of 140° C. overa period of 20 minutes while the reactor was stirring at 300 rpm andkept under 5 bar hydrogen. Once the autoclave reached 140° C., thehydrogen pressure was adjusted to 15 bar hydrogen and the stirring ratewas increased to 1700 rpm. The reaction was then started by pulsing 4milliliters of molten DNT into the reactor over 30 seconds with an HPLCpump. The HPLC pump head, the DNT reservoir and all the stainless tubingused for the transport of DNT was kept at 95° C. to keep the DNT molten.A Büchi hydrogen press flow controller (bpc 9901) was used to monitorthe hydrogen consumption and once the reaction stopped to consumehydrogen, another pulse of DNT was introduced at the same feed rate.This procedure was continued until a maximum of 45 pulses had beenintroduced. The data from these hydrogenations can be seen in graph 1,graph 2 and in data tables 3 to 13.

APPLICATION EXAMPLE 2

The batch hydrogenation of nitrobenzene to aniline.

The low pressure hydrogenation of nitrobenzene was carried out over 1.5grams of catalyst in 110 ml of a 9.1 wt % nitrobenzene ethanolicsolution at 25° C. and atmospheric pressure. A baffled glass reactoroutfitted with a bubbling stirrer spinning at 2000 rpm was used forthese hydrogenations. The results of these hydrogenations are listed intable 1.

TABLE 1 The batch nitrobenzene hydrogenation data. Nitrobenzene ActivityCatalyst ml H₂/min/gram catalyst Comparative Example 1 61 ComparativeExample 2 49 Example 7 80

APPLICATION EXAMPLE 3

The determination of the catalyst's ability to form nickel aluminates(e.g., takovite).

U.S. Pat. No. 6,423,872 describes a method for the determination of thecatalyst's ability to form nickel aluminates (e.g., takovite). Thismethod involved putting the catalyst together with TDA at thetemperature of 150° C. for 1 month. The tube was then opened and thecatalyst was examined by X-Ray diffraction. It was found that thecompound built up on the catalyst was takovite and its structure wasshown by X-Ray diffraction to be the same as that of the depositsobserved on the walls of an industrial DNT hydrogenation reactor and itsperipheral equipment.

We performed a similar test for our studies here.

To determine the catalyst's ability to form takovite, 0.2 grams of thecatalyst was placed together with 3.5 grams of a 63 wt % TDA and 37 wt %water mixture in a sealed tube for 3 weeks at 150° C. After the 3 weeks,the catalyst was removed and its takovite residues were analyzed byX-Ray diffraction. The takovite peak heights were then measured at the12, 24, 35, 40 and 47 °2 theta positions. The nickel peak height at the52 °2 theta position was also measured and it was the ratios of theindividual takovite peak heights to the nickel peak height that was usedto compare the different catalysts to each other. The relative ratiosfor these °2 theta positions were consistent enough for the differentcatalysts so that it was possible to consider using the ratio of the sumof the takovite peak heights for the 12, 24, 35, 40 and 47 °2 Thetapositions to the nickel peak height at 52 °2 theta for thisdetermination.

The data from these experiments are shown in table 2 and the catalystswith the higher takovite formation had the higher takovite-to-Ni peakheight ratios. By comparing the catalysts of the same Al content to eachother, one can see that the embodiments of this patent lead to lowerlevels of takovite formation. Only comparative example 1 (CE1) formed ahard version of takovite and the others examples described here onlyformed soft takovite, if they formed takovite at all.

TABLE 2 The x-ray diffraction data for the takovite deposits on the usedactivated nickel catalysts. Takovite peak heights (mm) at Ni at Ratio oftakovite peak heights to Example the below listed °2 ⊖ positions 52 theNi peak peak height number 12 24 35 40 47 °2⊖ 12 24 35 40 47 Sum CE1 4733 22 26 22.5 3.0 15.7 11 7.3 8.7 7.5 50.2 CE2 19.5 12.0 12.0 8.0 7.012.5 1.6 1.0 1.0 0.6 0.6 4.7 CE3 54 31.5 25.5 18.5 17 7.0 7.7 4.5 3.62.6 2.4 20.9 E1 12 8.0 8.0 6.0 5.0 15 0.8 0.5 0.5 0.4 0.3 2.6 E2 0.0 0.00.0 0.0 0.0 16.0 0.0 0.0 0.0 0.0 0.0 0.0 E3 12 8.0 8.0 5.0 4.5 15 0.80.5 0.5 0.3 0.3 2.5 E4 0.0 0.0 0.0 0.0 0.0 14 0.0 0.0 0.0 0.0 0.0 0.0 E523 12.5 12.0 8.0 7.0 12.5 1.8 1.0 1.0 0.6 0.6 5.0 E6 18.5 10.5 11.0 7.06.0 12.5 1.5 0.8 0.9 0.6 0.5 4.2 E8 0.0 0.0 0.0 0.0 0.0 13 0.0 0.0 0.00.0 0.0 0.0

COMPARATIVE EXAMPLE 1

An alloy containing Ni, Al, Cr and Fe was activated in an aqueous 20wt.-% NaOH suspension between 100 and 110° C. resulting in activated Nicatalyst containing 8.8 wt % Al, 2.5 wt % Cr and 2 wt % Fe with anaverage particle size value of 35 μm was tested for the formation oftakovite as described in application example 3. The ratio of the sum ofthe takovite x-ray diffraction peak heights at 12, 24, 35, 40 and 47 °2theta to the nickel x-ray diffraction peak height at 52 °2 theta wasfound to be 50.2. The individual takovite-to-nickel ratios of the x-raypeaks at 12, 24, 35, 40 and 47 °2 theta can be seen in table 2. Thiscatalyst was used for the batch hydrogenation of nitrobenzene to anilineas described in application example 2. The nitrobenzene hydrogenationactivity of this catalyst was found to be 61 ml H₂/min/gram of catalystand additional information can be seen in table 1. As described inapplication example 1, 150 milligrams of this catalyst were used for thepulse hydrogenation of dinitrotolunene to toluenediamine. Theselectivity of this reaction was greater than 90% toluenediamine and theactivity data points are given below in table 3 and graph 1.

TABLE 3 The dinitrotoluene hydrogenation data for comparative example 1.grams TDA yielded Hydrogenation Activity per gram of ml H₂ per minuteper gram of catalyst catalyst 15.5 1719 39.4 1258 59.1 1082 81.2 77599.7 692 116.4 591 137.9 515

COMPARATIVE EXAMPLE 2

An alloy containing Ni, Al and Fe was activated in an aqueous 20 wt.-%NaOH suspension between 100 and 110° C. resulting in an activated Nicatalyst containing 4 wt % Al, and 0.2 wt % Fe with an average particlesize value of 28 μm was tested for the formation of takovite asdescribed in application example 3. The ratio of the sum of the takovitex-ray diffraction peak heights at 12, 24, 35, 40 and 47 °2 theta to thenickel x-ray diffraction peak height at 52 °2 theta was found to be 4.7.The individual takovite-to-nickel ratios of the x-ray peaks at 12, 24,35, 40 and 47 °2 theta can be seen in table 2. This catalyst was usedfor the batch hydrogenation of nitrobenzene to aniline as described inapplication example 2. The nitrobenzene hydrogenation activity of thiscatalyst was found to be 49 ml H₂/min/gram of catalyst and additionalinformation can be seen in table 1. As described in application example1, 150 milligrams of this catalyst were used for the pulse hydrogenationof dinitrotolunene to toluenediamine. The selectivity of this reactionwas greater than 99% toluenediamine and the activity data points aregiven below in table 4 and graph 1.

TABLE 4 The dinitrotoluene hydrogenation data for comparative example 2.grams TDA yielded per gram of Hydrogenation Activity ml H₂ catalyst perminute per gram of catalyst 20 1575 31 1620 44 1842 59 1848 77 1893 961796 116 1644 137 1567 158 1520 179 1541 200 1586 222 1439 243 1488 2651533 288 1527 309 1456 333 1436 354 1469 375 1480 397 1422 418 1447 4401424 462 1393 484 1385 506 1370 528 1341 549 1259 571 1283 593 1183

COMPARATIVE EXAMPLE 3

An alloy containing Ni, Al, Cr and Fe was activated in an aqueous 20wt.-% NaOH suspension between 100 and 110° C. resulting in an activatedNi catalyst containing 6.3 wt % Al, 1.9 wt % Cr and 0.8 wt % Fe with anAPS value of 29 μm was tested for the formation of takovite as describedin application example 3. The ratio of the sum of the takovite x-raydiffraction peak heights at 12, 24, 35, 40 and 47 °2 theta to the nickelx-ray diffraction peak height at 52 °2 theta was found to be 20.9. Theindividual takovite-to-nickel ratios of the x-ray peaks at 12, 24, 35,40 and 47 °2 theta can be seen in table 2. As described in applicationexample 1, 150 milligrams of this catalyst were used for the pulsehydrogenation of dinitrotolunene to toluenediamine. The selectivity ofthis reaction was greater than 99% toluenediamine and the activity datapoints are given below in table 5 and graph 1.

TABLE 5 The dinitrotoluene hydrogenation data for comparative example 3.grams TDA yielded per gram of Hydrogenation Activity ml H₂ catalyst perminute per gram of catalyst 6 3154 18 3447 34 3587 51 3440 71 3175 893210 111 2924 129 3057 151 2808 172 2607 193 2521 214 2350 237 2273 2582223 280 2142 302 2070 324 2016 346 1764 367 1788 389 1618 411 1677 4321591 453 1486 473 1424 494 1380 514 1292 532 1216 552 1187

EXAMPLE 1

An alloy containing Ni, Al and Fe was activated in an aqueous 20 wt.-%NaOH suspension between 100 and 110° C. resulting in an activated Nicatalyst containing 3.43 wt % Al and 0.2 wt % Fe that was doped with anaqueous solution of CrO₃ to the final Cr content of 0.5 wt % Cr. Thiscatalyst had an APS value of 29 μm and was tested for the formation oftakovite as described in application example 3. The ratio of the sum ofthe takovite x-ray diffraction peak heights at 12, 24, 35, 40 and 47 °2theta to the nickel x-ray diffraction peak height at 52 °2 theta wasfound to be 2.6. The individual takovite-to-nickel ratios of the x-raypeaks at 12, 24, 35, 40 and 47 °2 theta can be seen in table 2. Asdescribed in application example 1, 150 milligrams of this catalyst wereused for the pulse hydrogenation of dinitrotolunene to toluenediamine.The selectivity of this reaction was greater than 99.5% toluenediamineand the activity data points are given below in table 6 and graph 1.Although the initial activity of this catalyst was lower than that ofCE3, this catalyst had a far lower rate of deactivation than the CE3 andit became more active than CE3 during the reaction and remained moreactive. As the reaction proceeded, the deactivation rate of the catalystbecame very close to zero. Hence, this catalyst is considerably betterthan CE3.

TABLE 6 The dinitrotoluene hydrogenation data for example 1. grams TDAyielded Hydrogenation Activity per gram of ml H₂ per minute per gram ofcatalyst catalyst 16 2678 30 2641 43 2965 61 2999 80 2965 100 3048 1203049 141 2802 163 2747 184 2785 204 2749 226 2713 247 2570 269 2644 2912521 312 2476 334 2521 356 2449 378 2369 400 2338 423 2223 445 2154 4672070 490 2044 511 1989 534 2011 556 1907 578 1910 600 1844 623 1900 6451799 668 1739 689 1664 712 1672 734 1622 755 1521

EXAMPLE 2

An alloy containing Ni, Al and Fe was activated in an aqueous 20 wt.-%NaOH suspension between 100 and 110° C. resulting in an activated Nicatalyst containing 3.46 wt % Al and 0.2 wt % Fe that was doped with anaqueous solution of CuSO₄ to the final Cu content of 0.1 wt % Cu. Thiscatalyst had an APS value of 29 μm and was tested for the formation oftakovite as described in application example 3. The ratio of the sum ofthe takovite x-ray diffraction peak heights at 12, 24, 35, 40 and 47 °2theta to the nickel x-ray diffraction peak height at 52 °2 theta wasfound to be 0.0. The individual takovite-to-nickel ratios of the x-raypeaks at 12, 24, 35, 40 and 47 °2 theta can be seen in table 2. Asdescribed in application example 1, 150 milligrams of this catalyst wereused for the pulse hydrogenation of dinitrotolunene to toluenediamine.The selectivity of this reaction was greater than 99.5% toluenediamineand the activity data points are given below in table 7 and graph 1.Although the initial activity of this catalyst was lower than that ofCE3, this catalyst had a far lower rate of deactivation than the CE3 andit became more active than CE3 during the reaction and remained moreactive. As the reaction proceeded, the deactivation rate of the catalystbecame very close to zero. Hence, this catalyst is considerably betterthan CE3. Unlike CE3, this catalyst does not form takovite and this willlead to further improvements in the use of this catalyst for thehydrogenation of nitro-compounds.

TABLE 7 The dinitrotoluene hydrogenation data for example 2. grams TDAyielded Hydrogenation Activity per gram of ml H₂ per minute per gram ofcatalyst catalyst 19 1821 34 1980 53 2021 74 1966 94 1871 117 1928 1391821 161 1797 184 1754 206 1714 229 1688 252 1671 274 1643 296 1576 3201558 342 1489 365 1527 388 1507 410 1481 433 1447 456 1419 478 1385 5011344 523 1316 546 1340 567 1303 591 1202 609 1218

EXAMPLE 3

An alloy containing Ni, Al and Fe was activated in an aqueous 20 wt.-%NaOH suspension between 100 and 110° C. resulting in an activated Nicatalyst containing 3.87 wt % Al and 0.22 wt % Fe that was doped with anaqueous solution of an ammonium molybdate salt to the final Mo contentof 0.11 wt % Mo. This catalyst had an APS value of 17 μm and was testedfor the formation of takovite as described in application example 3. Theratio of the sum of the takovite x-ray diffraction peak heights at 12,24, 35, 40 and 47 °2 theta to the nickel x-ray diffraction peak heightat 52 °2 theta was found to be 2.5. The individual takovite-to-nickelratios of the x-ray peaks at 12, 24, 35, 40 and 47 °2 theta can be seenin table 2. As described in application example 1, 300 milligrams ofthis catalyst were used for the pulse hydrogenation of dinitrotoluneneto toluenediamine. The selectivity of this reaction was greater than99.5% toluenediamine and the activity data points are given below intable 8 and graph 2

TABLE 8 The dinitrotoluene hydrogenation data for example 3. grams TDAyielded Hydrogenation Activity per gram of ml H₂ per minute per gram ofcatalyst catalyst 9 2449 18 2441 28 2572 39 2590 49 2560 60 2617 71 259781 2778 93 2633 104 2747 115 2694 126 2725 137 2594 148 2546 159 2510170 2546 181 2688 193 2535 204 2500 215 2546 226 2483 237 2556 249 2518260 2449 271 2389 283 2483 294 2372 305 2368 316 2416 328 2372 339 2334350 2305 362 2228 373 2119 384 2161 396 2117

EXAMPLE 4

An alloy containing Ni, Al and Fe was activated in an aqueous 20 wt.-%NaOH suspension between 100 and 110° C. resulting in an activated Nicatalyst containing 3.81 wt % Al and 0.21 wt % Fe that was doped with anaqueous solution of CuSO₄ to the final Cu content of 0.09 wt % Cu. Thiscatalyst had an APS value of 20 μm and was tested for the formation oftakovite as described in application example 3. The ratio of the sum ofthe takovite x-ray diffraction peak heights at 12, 24, 35, 40 and 47 °2theta to the nickel x-ray diffraction peak height at 52 °2 theta wasfound to be 0.0. The individual takovite-to-nickel ratios of the x-raypeaks at 12, 24, 35, 40 and 47 °2 theta can be seen in table 2. Asdescribed in application example 1, 300 milligrams of this catalyst wereused for the pulse hydrogenation of dinitrotolunene to toluenediamine.The selectivity of this reaction was greater than 99.5% toluenediamineand the activity data points are given below in table 9 and graph 2

TABLE 9 The dinitrotoluene hydrogenation data for example 4. grams TDAyielded Hydrogenation Activity per gram of ml H₂ per minute per gram ofcatalyst catalyst 10 2369 18 2384 25 2521 35 2467 45 2460 55 2348 662365 76 2536 87 2419 98 2614 110 2730 121 2676 133 2560 144 2544 1552432 167 2418 178 2526 190 2483 201 2517 213 2459 224 2475 236 2264 2472400 259 2271 270 2299 282 2320 293 2306 305 2210 316 2177 327 2223 3392230 350 2210 362 2115 374 2055 385 2051 396 1975

EXAMPLE 5

An alloy containing Ni, Al, Cr and Fe was activated in an aqueous 20wt.-% NaOH suspension between 100 and 110° C. resulting in an activatedNi catalyst containing 4.07 wt % Al, 0.73% Cr and 0.28 wt % Fe that wasdoped with an aqueous solution of an ammonium molybdate salt to thefinal Mo content of 0.1 wt % Mo. This catalyst had an APS value of 23 μmand was tested for the formation of takovite as described in applicationexample 3. The ratio of the sum of the takovite x-ray diffraction peakheights at 12, 24, 35, 40 and 47 °2 theta to the nickel x-raydiffraction peak height at 52 °2 theta was found to be 5.0. Theindividual takovite-to-nickel ratios of the x-ray peaks at 12, 24, 35,40 and 47 °2 theta can be seen in table 2. As described in applicationexample 1, 300 milligrams of this catalyst were used for the pulsehydrogenation of dinitrotolunene to toluenediamine. The selectivity ofthis reaction was greater than 99.5% toluenediamine and the activitydata points are given below in table 10 and graph 2

TABLE 10 The dinitrotoluene hydrogenation data for example 5. grams TDAyielded Hydrogenation Activity per gram of ml H₂ per minute per gram ofcatalyst catalyst 11 3004 21 3413 29 3020 39 3130 49 3724 60 3407 713603 82 3761 93 3983 105 3983 116 3815 128 3652 139 3876 151 3679 1623564 174 3547 185 3876 197 3356 208 3795 220 3860 231 3417 243 3582 2543519 266 3553 277 3588 289 3326 301 3433 312 3403 323 3502 335 3311 3463310 358 3162 369 3170 381 2968 393 3091 404 3028

EXAMPLE 6

An alloy containing Ni, Al, Cr and Fe was activated in an aqueous 20wt.-% NaOH suspension between 100 and 110° C. resulting in an activatedNi catalyst containing 4.1 wt % Al, 0.72% Cr and 0.28 wt % Fe that wasdoped with an aqueous solution of CuSO₄ to the final Cu content of 0.11wt % Cu. This catalyst had an APS value of 23 μm and was tested for theformation of takovite as described in application example 3. The ratioof the sum of the takovite x-ray diffraction peak heights at 12, 24, 35,40 and 47 °2 theta to the nickel x-ray diffraction peak height at 52 °2theta was found to be 4.2. The individual takovite-to-nickel ratios ofthe x-ray peaks at 12, 24, 35, 40 and 47 °2 theta can be seen in table2. As described in application example 1, 300 milligrams of thiscatalyst were used for the pulse hydrogenation of dinitrotolunene totoluenediamine except that 300 milligrams instead of 150 milligrams ofcatalyst was used. The selectivity of this reaction was greater than99.5% toluenediamine and the activity data points are given below intable 11 and graph 2

TABLE 11 The dinitrotoluene hydrogenation data for example 6. grams TDAyielded Hydrogenation Activity per gram of ml H₂ per minute per gram ofcatalyst catalyst 9 2863 16 2891 24 3370 32 3427 40 3399 49 3277 58 346967 3619 77 3469 86 3650 95 3347 105 3224 114 3543 124 3257 133 3257 1423091 152 3075 161 2992 171 3066 180 3045 189 2932 199 2844 208 2792 2183166 228 2970 237 2985 246 3064 256 2869 265 3097 275 3029 285 2805 2942983 304 2741 313 2705 322 2792 332 2766 341 2589 351 2927 361 2844 3702683

EXAMPLE 7

An alloy containing Ni, Al, Cr and Fe was activated in an aqueous 20wt.-% NaOH suspension between 100 and 110° C. resulting in an activatedNi catalyst containing 4.53 wt % Al, 1.51% Cr and 0.29 wt % Fe that wasdoped with an aqueous solution of an ammonium molybdate salt to thefinal Mo content of 0.13 wt % Mo. This catalyst had an APS value of 23μm. This catalyst was used for the batch hydrogenation of nitrobenzeneto aniline as described in application example 2. The nitrobenzenehydrogenation activity of this catalyst was found to be 80 mlH₂/min/gram of catalyst (please see table 1). As described inapplication example 1, 300 milligrams of this catalyst were used for thepulse hydrogenation of dinitrotolunene to toluenediamine. Theselectivity of this reaction was greater than 99.5% toluenediamine andthe activity data points are given below in table 12 and graph 2

TABLE 12 The dinitrotoluene hydrogenation data for example 7. grams TDAyielded Hydrogenation Activity per gram of ml H₂ per minute per gram ofcatalyst catalyst 9 3440 15 3046 20 3130 28 3344 37 3602 46 3627 56 391266 3888 76 3725 85 3535 95 3471 105 3398 114 3804 125 3575 134 3649 1443527 155 3490 164 3592 174 3763 184 3548 194 3583 204 3174 214 3202 2233291 233 3308 243 3344 253 3381 262 3420 271 3382 281 3079 290 3306 3003119 309 3104 318 2924 327 3168 337 3219 346 3015 355 3071 365 2853 3732867

EXAMPLE 8

An alloy containing Ni, Al and Fe was activated in an aqueous 20 wt.-%NaOH suspension in the presence of a fine Cr powder between 100 and 110°C. resulting in an activated Ni catalyst containing 3.92 wt % Al, 0.42%Cr and 0.22 wt % Fe. This catalyst had an APS value of 20 μm and wastested for the formation of takovite as described in application example3. The ratio of the sum of the takovite x-ray diffraction peak heightsat 12, 24, 35, 40 and 47 °2 theta to the nickel x-ray diffraction peakheight at 52 °2 theta was found to be 0.0. The individualtakovite-to-nickel ratios of the x-ray peaks at 12, 24, 35, 40 and 47 °2theta can be seen in table 2.

The results shown in the above examples clearly demonstrate that thepresent invention is well adapted to carry out the objectives and attainthe ends and advantages mentioned as well as those inherent therein.While increasing the Al content of the catalyst enhances its activity,it can also increase the amount of takovite produced during thehydrogenation of nitro-compounds such as dinitrotoluene. Hence in thepast, one had to select between either higher activity and the increasedpresence of takovite, or less catalyst activity (with lower Al contents)and less takovite. Stabilizing the Al in the catalyst by the inventionsof this patent will allow the practitioner of nitro-compoundhydrogenation to have both high activity and less takovite. Applicationexample 3 describes how we determined the ability of the catalyst toform takovite and the ratio of the sum of takovite °2 theta peak heightsto the Ni 52 °2 theta peak height normalizes this measurement withrespect to the XRD measured Ni quantity and this value is referred tohere as the takovite propensity. To compare the takovite propensities ofcatalysts containing different Al contents one should then divide thetakovite propensity by the wt. % Al to determine the relative amount ofAl in the catalyst that is leachable with a amino compounds such astoluenediamine (TDA) to form takovite. Another aspect is the activity ofthe catalyst. If the catalyst is highly active, one would need less ofthis catalyst to form the same amount of the desired amine. Hence themost important aspect of the takovite propensity is the relative amountof takovite formed with respect to catalyst activity and the wt. % Al.Since the dinitrotoluene hydrogenation experiments measured here go to aminimum of ˜350 grams of toluenediamine produced per gram of catalyst,we took the average activity up to 350 grams of toluenediamine per gramof catalyst as the standard comparison for our catalysts and thistogether with the relative amount of takovite formed with respect toactivity and Al content are listed in table 13. One can see from thedata that the proper selection of doping methods and doping elements cansurprisingly lead to a catalyst that has a high activity and forms a lowamount of takovite with respect to activity and Al content.

TABLE 13 The comparison of takovite formation with respect to Al contentand pulse dinitrotoluene hydrogenation activity. Relative amount ofTakovite Average with Activity respect to 350 g Ratio of Relative to wt% Al Doping APS TDA per wt. % Sum Takovite:Ni Activity and Catalystelements μm g cat Al Takovite:Ni to wt. % Al to CE2 Activity CE1 Cr, Fe35 379 8.8 50.2 5.70 0.24 24.08 CE2 Fe 28 1599 4 4.7 1.17 1.00 1.17 CE3Cr, Fe 29 2709 6.3 20.9 3.33 1.69 1.96 E1 Cr, Fe 29 2740 3.43 2.6 0.761.71 0.44 E2 Fe, Cu 29 1769 3.46 0.0 0.00 1.11 0.00 E3 Fe, Mo 17 25283.87 2.5 0.65 1.58 0.41 E4 Fe, Cu 20 2413 3.81 0.0 0.00 1.51 0.00 E5 Cr,Fe, 23 3548 4.07 5.0 1.23 2.22 0.55 Mo E6 Cr, Fe, 23 3089 4.1 4.2 1.021.93 0.53 Cu

While modification may be made by those skilled in the art, suchmodifications are encompassed within the spirit of the present inventionas defined by the disclosure and the claims.

The invention claimed is:
 1. An activated powder catalyst comprising: a)a Ni/Al alloy comprising one or more doping elements selected from thegroup consisting of Mg, V, Cr, Mo, Fe, Co, Pd and Pt, said dopingelements having been added before activation, and wherein said activatedpowder catalyst comprises 0.01 wt % to 5 wt % of each doping element;and b) Cu or Mo adsorbed on the surface of the activated powdercatalyst, said Cu or Mo having been adsorbed after activation, andwherein said activated powder catalyst comprises 0.01 wt % to 5 wt % ofsaid Cu or Mo; wherein said activated powder catalyst comprises 0.05 wt% to 10 wt % Al.
 2. The activated powder catalyst of claim 1, whereinsaid Ni/Al alloy comprises one or more doping elements selected from thegroup consisting of: Cr, Mo or Fe, said doping elements having beenadded before activation, and Cu is adsorbed on the surface of theactivated powder catalyst, said Cu having been adsorbed afteractivation.
 3. The activated powder catalyst of claim 1, wherein saidNi/Al alloy comprises one or more doping elements selected from thegroup consisting of: Mo, Cr or Fe, said doping elements having beenadded before activation and Mo is adsorbed on the surface of theactivated powder catalyst, said Mo having been adsorbed afteractivation.
 4. The activated powder catalyst of claim 1, wherein saidNi/Al alloy comprises the doping elements Cr and Fe, said dopingelements having been added before activation and Cu or Mo are adsorbedon the surface of the activated powder catalyst, said Cu or Mo havingbeen adsorbed after activation.
 5. A method for the hydrogenation of anitro-compound, comprising reacting said nitro compound with hydrogen inthe presence of the activated powder catalyst of claim
 1. 6. The methodof claim 5, wherein said nitro-compound is a nitrated aromatic.
 7. Themethod of claim 5, wherein said hydrogenation of said nitro-compound iscarried out continuously.
 8. The activated powder catalyst of claim 1,wherein Mo is adsorbed on the surface of the activated powder catalyst,said Mo having been adsorbed after activation.
 9. The activated powdercatalyst of claim 1, wherein Cu is adsorbed on the surface of theactivated powder catalyst, said Cu having been adsorbed afteractivation.
 10. The activated powder catalyst of claim 1, wherein saidactivated powder catalyst comprises 0.01 to 1.9 wt % of Fe.
 11. Theactivated powder catalyst of claim 1, wherein said activated powdercatalyst comprises 0.01 to 2.4 wt % Cr.
 12. The activated powdercatalyst of claim 1, wherein said activated powder catalyst comprises0.01 to 1.9 wt % of Fe and 0.01 to 2.4 wt. % Cr.
 13. The method of claim5, wherein the Ni/Al alloy in said activated powder catalyst comprisesone or more doping elements selected from the group consisting of Cr,Mo, or Fe, said doping elements having been added before activation, andCu is adsorbed on the surface of the activated powder catalyst, said Cuhaving been adsorbed after activation.
 14. The method of claim 5,wherein the Ni/Al alloy in said activated powder catalyst comprises oneor more doping elements selected from the group consisting of Cr, Mo, orFe, said doping elements having been added before activation, and Mo isadsorbed on the surface of the activated powder catalyst, said Mo havingbeen adsorbed after activation.
 15. The method of claim 5, wherein theNi/Al alloy in said activated powder catalyst comprises the dopingelements Cr and Fe, said doping elements having been added beforeactivation, and Cu or Mo is adsorbed on the surface of the activatedpowder catalyst, said Cu or Mo having been adsorbed after activation.16. The method of claim 5, wherein Mo is adsorbed on the surface of theactivated powder catalyst, said Mo having been adsorbed afteractivation.
 17. The method of claim 5, wherein Cu is adsorbed on thesurface of the activated powder catalyst, said Cu having been adsorbedafter activation.
 18. The method of claim 5, wherein said activatedpowder catalyst comprises 0.01 to 1.9 wt % Fe.
 19. The method of claim5, wherein said activated powder catalyst comprises 0.01 to 2.4 wt % Cr.20. The method of claim 5, wherein said activated powder catalystcontains 0.01 to 1.9 wt % Fe and between 0.01 and 2.4 wt % Cr.